1. Field of the Invention
This invention relates to the field of bandsaws and more particularly to a bandsaw having offset pulleys.
2. Description of the Prior Art
Bandsaws have been used for a variety of applications from cutting wood to slicing bread. These bandsaws typically employ two pulleys or wheels around which a belt forming the bandsaw blade travels. At least one of the pulleys is connected to a drive means which provides rotation to the pulley. As the pulley rotates, the bandsaw blade is carried along, thereby providing sufficient speed to the bandsaw blade to allow it to perform its cutting operation.
Typically, the bandsaws are of two types. In the first type of bandsaw, such as seen in bread slicers, the rotational planes of each of the pulleys are parallel and the pulleys have generally the same diameter. The bandsaw blade is wrapped around each pulley in such a manner as to provide two parallel cutting blade portions. The blade portions cut in separate kerfs and cut in opposing directions.
The second type of bandsaw employs parallel pulleys but operates the bandsaw blade in a figure 8 pattern. The bandsaw blade is twisted so that the cutting edge of the bandsaw blade is pointed in opposite directions on each of the pulleys. In such an arrangement, the bandsaw blade forms a figure 8 pattern. At the center point of the figure 8, where the opposing portions of the bandsaw blade intersect, the cutting edge of each portion of the bandsaw blade faces the same general direction. Moreover, each portion of the bandsaw blade cuts in the same kerf. In this manner, dual opposing cuts are made in the same kerf, thereby providing a more productive saw.
Each of these bandsaw designs are beset by problems which hinder their operability. In the first arrangement, if only a single cut is desired, the pulleys must be sufficiently large so that the second cutting blade portion will not interfere with the workpiece. As a result, only one portion of the bandsaw blade will be used in the cutting process. This creates an inefficiency which slows down production. The problems with the second design include the wear on the bandsaw blade as it follows an unnatural figure 8 path. The blade must be constantly adjusted to provide proper tracking of the belt around the pulleys. In addition, stresses build up on the bandsaw blade as a result of the forced twist, thereby causing early deterioration and failure of the blade. Moreover, because the opposing portions of the bandsaw blade do not cut in the same plane or closely parallel to one another, such a bandsaw is unable to handle intricate cutting operations such as those needed to cut a radius in the workpiece. Consequently, there is a need for a bandsaw in which two blade portions cut in a single kerf. Moreover, there is a need for a bandsaw which provides a more natural dual cutting action which will not cause premature failure of the blade.